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Biomedical subjects

W D Wong

Publications and source records attributed to W D Wong.

At least 19 recordsLinked to original sources
PubMed1998

Incontinence after lateral internal sphincterotomy: anatomic and functional evaluation.

PURPOSE: This study was designed to evaluate the anatomic and functional consequences of lateral internal sphincterotomy in patients who developed anal incontinence and in matched controls. METHODS: The study includes 13 patients with anal incontinence after lateral internal sphincterotomy and 13 controls who underwent the same operation and were continent and satisfied with the results of the procedure. Patients underwent clinical evaluation, anorectal manometry, pudendal nerve terminal motor latency testing, and endoanal ultrasonography. RESULTS: Sphincterotomies were longer in incontinent patients (75 vs. 57 percent), but the resting pressure and length of the high-pressure zone were not different between groups. Surprisingly, maximum voluntary contraction was higher in incontinent patients than in continent controls (136 vs. 100 mmHg). Rectal sensation and pudendal nerve terminal motor latency were similar in both groups. The defect in the internal sphincter was wider in incontinent patients than in continent controls (17.3 vs. 14.4 mm), but these differences were not statistically significant. The thickness of the internal sphincter measured by endoanal ultrasound was identical in both groups, but the external sphincter was thinner in incontinent patients both at the site of the sphincterotomy (6.8 vs. 8.1 mm) and in the posterior midline (7.1 vs. 8.6 mm). CONCLUSIONS: Anal incontinence after lateral internal sphincterotomy is directly related to the length of the sphincterotomy. Whether secondary to preoperative sphincter abnormality or the result of lateral internal sphincterotomy, the external sphincter is thinner in incontinent patients than in continent controls.

Adult↗
PubMed1998

Perineal body measurement improves evaluation of anterior sphincter lesions during endoanal ultrasonography.

UNLABELLED: Endoanal ultrasonography has become an important tool in the evaluation of patients with anal incontinence. However, the extent of anterior defects is sometimes difficult to quantitate during endoanal ultrasonography. PURPOSE: This study was designed to evaluate perineal body measurement during endoanal ultrasonography in assessing patients with obstetric anal sphincter injuries. METHODS: Forty-two patients with anal incontinence because of obstetric sphincter injuries and 13 asymptomatic subjects were investigated with endoanal ultrasonography. Sphincter muscle thickness, sphincter defects, and perineal body were measured. Perineal body measurement was performed by inserting a finger, held gently against the posterior vaginal wall, into the vagina and measuring the distance between the inner surface of the internal sphincter and the ultrasonographic reflection of the finger. RESULTS: All patients had anterior sphincter lesions of varying extent. Mean size of internal sphincter lesions was 146 degrees, and mean size of external sphincter lesions was 107 degrees (P < 0.001). Perineal body measurement was performed without difficulty in all patients and subjects. Perineal body measurement (mean +/- standard deviation) was 6 +/- 2 mm in patients and 12 +/- 3 mm in asymptomatic subjects (P < 0.001). Ninety-three percent of patients had perineal body measurement < or = 10 mm, and 70 percent of asymptomatic subjects had perineal body measurement > 10 mm. Digital delineation of the perineal body during endoanal ultrasonography improved the visualization of sphincter lesions in 74 percent of patients. CONCLUSIONS: Digital delineation of the perineal body during endoanal ultrasonography improved the visualization of sphincter lesions in the majority of patients. Perineal body measurement is performed without difficulty and is a good predictor of anterior sphincter lesions. Use of this technique improves visualization of sphincter lesions.

Adult↗
PubMed1998

Should patients with combined colonic inertia and nonrelaxing pelvic floor undergo subtotal colectomy?

PURPOSE: Treatment of severe constipation caused by combined colonic inertia and nonrelaxing pelvic floor is controversial. This study is designed to evaluate the outcome of preoperative biofeedback and subtotal colectomy for patients with combined colonic inertia and nonrelaxing pelvic floor. METHODS: One hundred six patients who underwent subtotal colectomy for intractable constipation from 1982 through 1995 answered a detailed questionnaire regarding postoperative bowel function, symptoms of abdominal pain and bloating, and degree of satisfaction after the operation. Sixteen of these patients had a combination of colonic inertia and nonrelaxing pelvic floor diagnosed by transit marker study, electromyography, and defecography. These patients completed preoperative biofeedback training. RESULTS: Electromyographic relaxation of pelvic floor musculature was demonstrated after the biofeedback treatment in all patients, but symptoms of difficult evacuation persisted. Postoperatively, seven patients (43 percent) had complete resolution of symptoms of constipation or difficult evacuation. Six patients still complained of incomplete evacuation that was severe in two and unresponsive to postoperative biofeedback. Three patients (18 percent) complained of diarrhea (>5 bowel movements per day) and incontinence of liquid stools (at least one episode a week). Nine patients (56 percent) were satisfied despite persistent symptoms. CONCLUSIONS: Subtotal colectomy can improve some symptoms in patients with slow transit constipation and nonrelaxing pelvic floor. However, incomplete evacuation persists in a significant number of patients and almost one-half of patients are dissatisfied with their surgery.

Adult↗
PubMed1998

Accuracy and reliability of transanal ultrasound for anterior anal sphincter injury.

INTRODUCTION: Although transanal ultrasound has rapidly become the test of choice for the diagnosis of anal sphincter injury, the accuracy and reliability of this technique are unknown. This study evaluates the accuracy and reliability of transanal ultrasound for anterior (obstetric-related) anal sphincter injury. METHODS: Sixty-two women underwent transanal ultrasound with hard-copy images obtained at 0.5-cm intervals from the anal verge to 2.5 cm into the anal canal. All transanal ultrasound procedures were also recorded on videotape. Two experienced ultrasonographers blinded as to the patients' clinical history and examination independently reviewed the images and videotape recordings for the presence or absence of anal sphincter injury. RESULTS: The accuracy of transanal ultrasound in 22 incontinent women with known anal sphincter injury was 100 percent. The accuracy of transanal ultrasound in 20 nulliparous women with intact anal sphincters was only 35 percent but improved to 50 percent after the "real time" videotape was reviewed (P = 0.16) and further improved to 85 percent when interpretation was limited to the distal 1.5 cm of the anal canal (P = 0.004). In these nulliparous women, intact internal sphincters were more accurately predicted than intact external sphincters (95 vs. 85 percent; P = 0.24). Measurement agreement between the two ultrasonographers was 68 percent (fair; kappa, 0.26) but significantly improved to 78 percent (moderate; kappa, 0.48; P = 0.0001) when interpretation was limited to the distal 1.5 cm of the anal canal. Overall clinical agreement (final scan interpretation) was good (81 percent agreement; kappa, 0.61). Agreement was better for the internal sphincter (74 percent; fair; kappa, 0.36) than the external sphincter (61 percent; poor; kappa, 0.17; P = 0.0002). CONCLUSIONS: Although transanal ultrasound can accurately identify anterior anal sphincter injury when present, transanal ultrasound falsely identifies sphincter injury in at least 5 to 25 percent of normal anal sphincters. Only fair agreement in the interpretation of transanal ultrasound exists between experienced ultrasonographers. Both the accuracy and reliability of transanal ultrasound are significantly improved by limiting transanal ultrasound to the distal 1.5 cm of the anal canal.

Adult↗
PubMed1998

Anal sphincter integrity and function influences outcome in rectovaginal fistula repair.

PURPOSE: Traumatic sphincter disruption frequently is associated with a rectovaginal fistula, but the effect of a persistent sphincter defect on the outcome of rectovaginal fistula repair is poorly documented. We analyzed the outcome of rectovaginal fistula repairs based on preoperative sphincter status. PATIENTS AND METHODS: We identified 52 women who underwent 62 repairs of simple obstetrical rectovaginal fistulas between 1992 and 1995. Fourteen patients (27 percent) had preoperative endoanal ultrasound studies and 25 (48 percent) had anal manometry studies. Follow-up was by mailed questionnaire in 36 patients (69 percent) and by telephone interview in 12 (23 percent), for a total response rate of 92 percent. Median age was 30.5 (range, 18-70) years, and median follow-up was 15 (range, 0.5-123) months. Twenty-five patients (48 percent) complained of varying degrees of fecal incontinence before surgery. There were 27 endorectal advancement flaps and 35 sphincteroplasties (28 with and 8 without levatoroplasty). RESULTS: Success rates were 41 percent with endorectal advancement flaps and 80 percent with sphincteroplasties (96 percent success with and 33 percent without levatoroplasty; P = 0.0001). Endorectal advancement flap was successful in 50 percent of patients with normal sphincter function but in only 33 percent of patients with abnormal sphincter function (P = not significant). For sphincteroplasties, success rates were 73 vs. 84 percent for normal and abnormal sphincter function, respectively (P = not significant). Results were better after sphincteroplasties vs. endorectal advancement flaps in patients with sphincter defects identified by endoanal ultrasound (88 vs. 33 percent; P = not significant) and by manometry (86 vs. 33 percent; P = not significant). Poor results correlated with prior surgery in patients undergoing endorectal advancement flaps (45 percent vs. 25 percent; P = not significant) but not sphincteroplasties (80 vs. 75 percent; P = not significant). CONCLUSIONS: All patients with rectovaginal fistula should undergo preoperative evaluation for occult sphincter defects by endoanal ultrasound or anal manometry or both procedures. Local tissues are inadequate for endorectal advancement flap repairs in patients with sphincter defects and a history of previous repairs. Patients with clinical or anatomic sphincter defects should be treated by sphincteroplasty with levatoroplasty.

Adolescent↗
PubMed1997

Computed tomography-guided percutaneous abscess drainage in intestinal disease: factors associated with outcome.

PURPOSE: This study was designed to assess the efficacy of computed tomography-guided percutaneous abscess drainage in intestinal disease. METHODS: Retrospective chart review of patients who underwent percutaneous abscess drainage for complications of intestinal disease with or without surgery between 1990 and 1994. RESULTS: Eighty-two patients with 111 abscesses were identified. Causes of abscess included anastomotic leaks (35 percent), postoperative complications without leak (30 percent), and diverticular disease (23 percent). Complete success (no surgery necessary) was achieved in 53 of 82 patients (65 percent). Nine patients (11 percent) who underwent interval surgery were classified as having partial successes. Twenty-six of 26 (100 percent) well-defined unilocular collections containing pus were successfully drained. Complex abscesses (loculated, poorly defined, multiple, associated with fistula, draining feces) were successfully drained in 35 of 55 patients (63 percent). Success rates varied inversely with the number of complicating factors present. Apache II scores of 15 or higher were associated with decreased success rates. CONCLUSION: Percutaneous abscess drainage is a highly successful technique for treatment of patients with intra-abdominal infection related to intestinal disease. Although several factors are associated with decreased success rates and multiple complicating factors combine to reduce success rates, no identifiable factor or combination of factors preclude the possibility of a successful outcome.

Abscess↗
PubMed1997

Immunohistochemical localization of insulin-degrading enzyme along the rat intestine, in the human colon adenocarcinoma cell line (Caco-2), and in human ileum.

Insulin-degrading enzyme (IDE) has been implicated in the intracellular degradation of insulin in insulin target cells. Knowledge of the existence of this enzyme in the intestine will be beneficial to the achievement of clinical oral efficacy of insulin. A comparative study was conducted with rat intestine, human colon adenocarcinoma (Caco-2) cells, and human ileum. Confocal microscopy analysis using the anti-IDE antibody showed that IDE was localized in the mucosal cells of rat and human intestines, as well as in Caco-2 cells. Immunostaining of this enzyme was homogeneous throughout the cell excluding nucleus, indicating a typical cytosolic distribution in rat and human enterocytes and in Caco-2 cells.

Adenocarcinoma↗
PubMed1997

Experimental model of pudendal nerve innervation of a skeletal muscle neosphincter for faecal incontinence.

BACKGROUND: Faecal incontinence is difficult to treat. A variety of reconstructive procedures has been described, but none is entirely satisfactory. This study evaluated the feasibility of cross-innervating a skeletal muscle neosphincter with the pudendal nerve in a canine model. METHODS: Thirty dogs were rendered surgically incontinent (the pudendal nerve was cut and the external sphincter was partially excised). A neosphincter was then created using the semitendinosus muscle. In ten dogs pudendal nerve transposition (PNT) to the nerve to the semitendinosus muscle was performed. Ten dogs were given a dynamic neosphincter by inserting a pulse generator at 6 weeks. The remaining ten dogs served as controls with passive semitendinosus wraps. Anal manometry was performed before operation and monthly for 5 months. Muscle biopsies, performed at the initial operation and at 5 months, were stained for slow- and fast-twitch fibres, and were examined histologically. RESULTS: At 1 month, mean sphincter function was 32 per cent of the preoperative value in the control animals, 34 per cent in the PNT group and 27 per cent in the electrostimulation group; all dogs were incontinent. At 5 months the mean recovery of sphincter function was 42 per cent of the preoperative value in controls, 100 per cent in dogs with PNT (P < 0.001) and 63 per cent in dogs having electrostimulation (stimulator on) (P = 0.02). Six dogs with PNT had squeeze pressures equal to or greater than preoperative levels. At 5 months the ratio of slow to fast fibres was significantly greater in all dogs (control P = 0.01, PNT P < 0.005, electrostimulation P < 0.001). CONCLUSION: Use of the pudendal nerve to innervate a canine skeletal muscle anal wrap produced a functional anal sphincter that was superior to electrically stimulated and passive wraps.

Anal Canal↗
PubMed1996

The Hartmann procedure. First choice or last resort in diverticular disease?

OBJECTIVE: To critique changing trends in the surgical management of diverticular disease. DESIGN: Case series. Two hundred twenty-seven consecutive patients required surgery for diverticular disease from 1988 to 1993. Patient records were reviewed retrospectively. Operative procedures included primary resection in all patients with either anastomosis, anastomosis with proximal ileostomy, or the Hartmann procedure. Morbidity, mortality, and length of stay were then compared with each operative procedure and stage of disease. Patients were categorized according to the following pathologic stages: stage 0, no inflammation; stage I, chronic inflammation; stage II, acute inflammation with or without microabscesses; stage III, pericolonic or mesenteric abscess; stage IV, pelvic abscess; and stage V, purulent or feculent peritonitis. SETTING: A university hospital and private affiliated hospitals in a large metropolitan area. MAIN OUTCOME MEASURES: Study outcome parameters included mortality, morbidity, length of hospital stay, and leak rates. These outcomes were then compared with different disease stages and treatments. RESULTS: Mean patient age was 66 years (range, 25-98 years). Male-female ratio was 84:143. Mean follow-up was 23 months (range, 1-132 months). There were 50 fistulas: 24 colovesical, 21 colovaginal, 3 colocolonic, 1 coloenteric, and 1 colouterine. Surgery was categorized as elective for 196 patients (86%), urgent for 12 (5%), and emergent for 19 (8%). Primary resection was performed in all cases. Primary anastomosis was performed in 200 patients (88%), 183 without and 17 with proximal diversion. Twenty-seven patients (12%) underwent a Hartmann procedure with colostomy; 19 patients (70%) have since undergone colostomy closure. Morbidity occurred in 52 patients (23%), including 4 anastomotic leaks (2%). There were 3 perioperative deaths (1%). Mean length of initial hospital stay was 11 days (range, 4-59 days). Length of stay was 5 days (range, 4-7 days) for ileostomy closure (7% morbidity) and 13 days (range, 7-35 days) for the colostomy closure after the Hartmann procedure (33% morbidity). CONCLUSIONS: Primary resection is virtually always possible in complicated diverticular disease. Primary anastomosis, with or without proximal diversion, is safe for patients with no abscesses or localized abscesses and should be considered on an individual basis for patients with pelvic abscesses and peritonitis. Colostomy closure after the Hartmann procedure is associated with significant length of hospitalization and morbidity and leaves one third of patients with permanent stomas.

Adult↗
PubMed1996

Carcinoid tumor: an extremely unusual presacral lesion. Report of a case.

PURPOSE: Use of endorectal ultrasonography in preoperative evaluation of a presacral lesion is demonstrated. METHOD: The natural history, presentation, evaluation, and treatment of presacral lesions in adult patients are presented. The case of a female patient with a presacral carcinoid tumor is presented and discussed. RESULTS: The patient underwent preoperative evaluation including physical examination, hematologic studies, proctosigmoidoscopy, magnetic resonance imaging, computed tomographic scanning, and endorectal ultrasonography. Ultrasonography proved to be extremely valuable in differentiating tumor compression from tumor invasion of the rectal wall. The patient underwent en bloc excision of the lesion, surrounding tissue, and coccyx. Pathologic diagnosis was carcinoid tumor, possibly replacing a presacral lymph node. Postoperative complete gastrointestinal tract work-up and urinary 5-hydroxyindoleacetic acid analysis along with preoperative imaging revealed no evidence of synchronous lesions or additional metastases. CONCLUSIONS: Presacral lesions are extremely rare entities. The role of endorectal ultrasonography has not been clearly defined. This case demonstrates the value of this simple and safe imaging procedure in detecting bowel wall compression vs. invasion, greatly assisting in planning an operative approach.

Carcinoid Tumor↗
PubMed1996

Open vs. closed sphincterotomy for chronic anal fissure: long-term results.

PURPOSE: This study was undertaken to compare the healing rate and long-term effects on continence of open and closed lateral internal sphincterotomy. METHODS: Charts of 864 patients with chronic anal fissure who underwent internal sphincterotomy as a single procedure over five years by a group of 12 colorectal surgeons were reviewed. Open internal sphincterotomy (OIS) was performed in 521 patients, whereas 343 had closed internal sphincterotomy (CIS). There was no difference in sex or age between the groups. A questionnaire inquiring about clinical outcome, changes in continence, and degree of satisfaction with the procedure was mailed to all patients. A total of 549 (63.5 percent) patients, 324 (62.2 percent) with OIS and 225 (65.6 percent) with CIS, returned their questionnaires. Average follow-up was three (range, 1-6) years. RESULTS: Differences in persistence of symptoms (3.4 OIS vs. 5.3 percent CIS), recurrence of the fissure (10.9 vs. 11.7 percent CIS), and need for reoperation (3.4 percent OIS vs. 4 percent CIS) were statistically not significant. However, statistically significant differences were seen in the percentage of patients with permanent postoperative difficulty controlling gas (30.3 vs. 23.6 percent; P 0.062), soiling underclothing (26.7 vs. 16.1 percent; P < 0.001), and accidental bowel movements (11.8 vs. 3.1 percent; P < 0.001) between those who underwent OIS and those who had CIS. Although 90 percent of patients reported general overall satisfaction, more patients undergoing CIS (64.4 percent) than OIS (49.7 percent) were very satisfied with the results of the procedure. CONCLUSIONS: Lateral internal sphincterotomy is highly effective in treatment of chronic anal fissure but is associated with significant permanent alterations in continence. CIS is preferable to OIS because it effects a similar rate of cure with less impairment of control.

Adult↗
PubMed1996

Anal fistula surgery. Factors associated with recurrence and incontinence.

PURPOSE: This study was undertaken to assess results of surgery for fistula-in-ano and identify risk factors for fistula recurrence and impaired continence. METHODS: We reviewed the records of 624 patients who underwent surgery for fistula-in-ano between 1988 and 1992. Follow-up was by mailed questionnaire, with 375 patients (60 percent) responding. Mean follow-up was 29 months. Fistulas were intersphincteric in 180 patients, transsphincteric in 108, suprasphincteric in 6, extrasphincteric in 6, and unclassified in 75. Procedures included fistulotomy and marsupialization (n = 300), seton placement (n = 63), endorectal advancement flap (n = 3), and other (n = 9). Factors associated with recurrence and incontinence were analyzed by univariate and multivariate regression analysis. RESULTS: The fistula recurred in 31 patients (8 percent), and 45 percent complained of some degree of postoperative incontinence. Factors associated with recurrence included complex type of fistula, horseshoe extension, lack of identification or lateral location of the internal fistulous opening, previous fistula surgery, and the surgeon performing the procedure. Incontinence was associated with female sex, high anal fistula, type of surgery, and previous fistula surgery. CONCLUSIONS: Surgical treatment of fistula-in-ano is associated with a significant risk of recurrence and a high risk of impaired continence. Degree of risk varies with identifiable factors.

Fecal Incontinence↗
PubMed1996

Artificial anal sphincter.

PURPOSE: This study was undertaken to evaluate the use of a fully implanted artificial anal sphincter for management of severe fecal incontinence. METHODS: An artificial anal sphincter was implanted in 12 patients who failed conventional management for severe fecal incontinence. Careful patient follow-up was recorded during a mean 58-month follow-up. Patients underwent preoperative and postoperative manometric assessment. Functional and patient satisfaction evaluations were obtained by mailed questionnaire. RESULTS: Three infections and three mechanical complications occurred in four patients (33 percent). A successful outcome was achieved in nine patients (75 percent). Postoperative manometric studies documented establishment of an elevated high-pressure zone compared with preoperative resting pressures. Seven patients returned a detailed functional assessment and patient satisfaction questionnaire at a mean of 40 months postsphincter activation. All seven patients reported continence to solid stool. Two patients had some problems with control of liquid stool, and three had occasional incontinence to flatus. Six of the seven patients rated their bowel control as good to excellent. All seven respondents were satisfied with their functional improvement. CONCLUSIONS: Early experience with an artificial anal sphincter has demonstrated that continence can be restored with acceptable morbidity in patients with severe fecal incontinence.

Activities of Daily Living↗
PubMed1996

Preoperative adjuvant radiation with chemotherapy for rectal cancer: its impact on stage of disease and the role of endorectal ultrasound.

BACKGROUND: Preoperative adjuvant radiation combined with chemotherapy is a recent development in the management of patients with rectal cancer invading perirectal tissue and regional lymph nodes. This study was performed to assess the impact of preoperative adjuvant therapy in patients judged by endorectal ultrasound to have extramural invasion of rectal cancer and/or regional lymph node involvement on tumor regression in bowel wall and lymph nodes. The predictive value of ultrasound in staging wall penetration and lymph node involvement after preoperative adjuvant therapy was also assessed. METHODS: Patients (n = 43) were selected by ultrasound to have preoperative irradiation (4,500-5,040 cGy over 5-6 weeks). In 30 patients this was combined with 5-fluorouracil, 370 mg/m(2), for 5 days in the first and last weeks of irradiation. Pretreatment ultrasound was compared with pathologic findings in the resected specimen in all patients. Twenty-one were assessed by ultrasound after adjuvant therapy and findings compared with histology. RESULTS: Downstaging was seen in 23 (53%) patients with wall invasion and in 23 (72%) of 32 patients with lymph node involvement. Overall, downstaging was achieved in 30 (70%). Positive predictive values of ultrasound after irradiation were 72% and 56% for wall penetration and lymph node status, respectively. Negative predictive values of ultrasound after irradiation were 100% and 82%, respectively. CONCLUSION: In the majority of patients with rectal cancer invading perirectal tissues or lymph nodes, lesions may be downstaged by preoperative adjuvant therapy. Endorectal ultrasound after adjuvant therapy for rectal cancer is of a lesser predictive value chiefly because of overstaging.

Adult↗
PubMed1996

The presence of insulin-degrading enzyme in human ileal and colonic mucosal cells.

The aim of this research is to characterize the presence of insulin-degrading enzyme in human colon and ileal mucosal cells. Biochemical studies, including the activity-pH profiles, the effects of enzyme inhibitors, immunoprecipitation and western blots, were conducted. The majority of insulin-degrading activity in colon mucosal cells was localized in the cytosol. In both colon and ileum, cytosolic insulin-degrading activities had a pH optimum at pH 7.5, and were extensively inhibited by each of N-ethylmaleimide, p-chloromercuribenzoate, and 1,10-phenanthroline, but were very weakly affected by each of leupeptin, chymostatin, diisopropyl phosphofluoridate and soybean trypsin inhibitor. In the colon and ileum, more than 93% and 96%, respectively, of cytosolic insulin-degrading activities were removed by the mouse monoclonal antibody to human RBC insulin-degrading enzyme, as compared with less than 20% by the normal mouse IgG for both tissues. Further, a western blot analysis revealed that a cytosolic protein of 110 kD, in both human colon and ileum, reacted with the monoclonal antibody to insulin-degrading enzyme. It is concluded that insulin-degrading enzyme is present in the cytosol of human colon and ileal mucosal cells.

Animals↗